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      <title>2、线程的实现 - 交互式测验</title>
      <style>
        @import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@400;500;700&display=swap');
        
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          padding: 20px;
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            max-width: 900px; /* Wider to accommodate buttons */
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          border-radius: 16px;
          box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
          width: 100%;
          max-width: 700px;
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          z-index: 10;
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        .quiz-header {
          background-color: #4a90e2;
          color: white;
          padding: 20px 30px;
          text-align: center;
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        .quiz-header h1 {
          margin: 0;
          font-size: 24px;
          font-weight: 700;
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        .quiz-header p {
            margin: 5px 0 0;
            font-size: 14px;
            opacity: 0.9;
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        .quiz-body {
          padding: 30px;
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        .progress-bar {
            display: none; /* 隐藏进度条 */
            width: 100%;
            background-color: #e0e0e0;
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            height: 10px;
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        #question-text {
          font-size: 18px;
          font-weight: 500;
          line-height: 1.6;
          margin-bottom: 25px;
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        .option-item {
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          border: 1px solid #dee2e6;
          border-radius: 8px;
          padding: 15px;
          margin-bottom: 12px;
          cursor: pointer;
          transition: background-color 0.2s ease, border-color 0.2s ease;
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        .option-item:hover {
          background-color: #e9ecef;
        }
        
        .option-item.selected {
            background-color: #d1e7fd;
            border-color: #4a90e2;
        }

        .quiz-footer {
          padding: 20px 30px;
          display: flex;
          justify-content: space-between; /* 将按钮分布在两侧 */
          align-items: center;
          min-height: 65px; /* Reserve space */
        }

        .nav-btn {
          background-color: #4a90e2;
          color: white;
          border: none;
          border-radius: 8px;
          padding: 10px 20px;
          font-size: 16px;
          font-weight: 500;
          cursor: pointer;
          transition: background-color 0.2s ease, transform 0.2s ease;
          box-shadow: 0 4px 12px rgba(0,0,0,0.15);
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        #next-btn {
            background-color: #28a745;
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        .nav-btn:hover {
          background-color: #357abd;
          transform: scale(1.05);
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        .nav-btn:disabled {
            background-color: #a0c3e8;
            cursor: not-allowed;
            opacity: 0.7;
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        #result-container {
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        }
        
        .result-box {
            border-radius: 8px;
            padding: 20px;
            margin-top: 20px;
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        .result-box.correct {
            background-color: #d4edda;
            border: 1px solid #c3e6cb;
            color: #155724;
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        .result-box.incorrect {
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            border: 1px solid #f5c6cb;
            color: #721c24;
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        .result-box h3 {
            margin-top: 0;
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        .explanation-text {
            margin-top: 15px;
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        .source-text {
            font-style: italic;
            font-size: 14px;
            margin-top: 15px;
            color: #555;
        }

        
        .final-score-container {
            padding: 40px;
            text-align: center;
        }
        .final-score-container h2 {
            margin-top: 0;
            margin-bottom: 30px;
        }
        .score-summary {
            display: flex;
            justify-content: center;
            gap: 20px;
            margin-bottom: 40px;
            flex-wrap: wrap;
        }
        .score-card {
            background-color: #f8f9fa;
            border-radius: 12px;
            padding: 20px;
            width: 180px;
            box-shadow: 0 4px 12px rgba(0,0,0,0.05);
            border: 1px solid #e9ecef;
        }
        .score-card h3 {
            margin: 0 0 10px;
            font-size: 16px;
            font-weight: 500;
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        .score-card p {
            margin: 0;
            font-size: 28px;
            font-weight: 700;
            color: #333;
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        .score-details table {
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            font-size: 16px;
        }
        .score-details td {
            padding: 4px 0;
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        .score-details td:last-child {
            text-align: right;
            font-weight: 700;
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        .report-actions button {
            background-color: #fff;
            border: 1px solid #ccc;
            border-radius: 8px;
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            margin: 0 10px;
            transition: background-color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
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        .report-actions button:hover {
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            color: white;
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        .report-actions button.primary:hover {
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        .hint-container {
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            border: 1px solid #b2ebf2;
            border-radius: 8px;
            padding: 15px;
            margin-top: 20px;
            color: #006064;
            font-size: 15px;
            line-height: 1.6;
            display: none; /* 默认隐藏 */
        }
      </style>
    </head>
    <body>
      <div class="main-wrapper">
          <div class="quiz-container">
            <div class="quiz-header">
              <h1>2、线程的实现 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
            </div>
            <div id="quiz-content">
                <div class="quiz-body">
                    <div class="progress-bar">
                        <div id="progress-indicator"></div>
                    </div>
                    <div id="question-container">
                      <p id="question-text"></p>
                      <ul class="options-list" id="options-list"></ul>
                    </div>
                    <div id="result-container"></div>
                    <div id="hint-container" class="hint-container"></div>
                </div>
                <div class="quiz-footer" id="quiz-footer">
                  <button id="prev-btn" class="nav-btn">上一题</button>
                  <button id="hint-btn" class="nav-btn" style="background-color: #ffc107; color: #333; box-shadow: 0 4px 12px rgba(255,193,7,0.3);">提示</button>
                  <button id="next-btn" class="nav-btn">下一题</button>
                </div>
            </div>
          </div>
      </div>

      <script>
        const quizData = [
  {
    "question": "根据文档，与进程（Process）相比，线程（Thread）最核心的区别是什么？",
    "options": [
      "线程的创建和切换开销比进程大。",
      "进程是操作系统分配资源的最小单位，拥有独立的内存空间；而线程共享所属进程的内存空间和资源。",
      "进程之间可以直接进行数据交换，而线程间通信需要复杂的机制。",
      "线程是操作系统执行的最小单位，而进程是程序内部的一条执行路径。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档明确指出，进程是操作系统分配资源的最小单位，拥有独立的内存空间。而线程作为进程的子任务，可以共享进程的内存空间和资源。这使得线程间的通信更直接、创建和切换的开销更小。",
    "source": "文档中「线程与进程的区别」部分",
    "hint": "思考一下资源分配的基本单位是什么，以及它们在内存管理上的根本不同。"
  },
  {
    "question": "在Java中创建一个可以返回执行结果的线程，最适合使用哪种方式？",
    "options": [
      "继承 Thread 类并重写 run() 方法。",
      "实现 Runnable 接口并实现 run() 方法。",
      "实现 Callable 接口，并配合 Future 来获取结果。",
      "使用 synchronized 关键字创建一个同步代码块。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "文档中提到，`Callable` 接口的 `call()` 方法可以返回一个执行结果，并且可以抛出异常。这与 `Runnable` 的 `run()` 方法（无返回值）形成了鲜明对比。通常使用 ExecutorService 提交 Callable 任务，并通过返回的 Future 对象来异步获取结果。",
    "source": "文档中「线程实现方式」-「使用Callable和Future」部分",
    "hint": "文档介绍了三种创建线程的方式，哪一种特别提到了“返回执行结果”？"
  },
  {
    "question": "当一个线程对象被创建后，但在调用 `start()` 方法之前，它处于线程生命周期的哪个状态？",
    "options": [
      "就绪状态 (Runnable)",
      "运行状态 (Running)",
      "新建状态 (New)",
      "阻塞状态 (Blocked)"
    ],
    "correctAnswerIndex": 2,
    "explanation": "根据文档对线程生命周期的描述，当线程对象被创建后，它就处于“新建状态（New）”。只有在调用了 `start()` 方法之后，线程才会进入“就绪状态（Runnable）”，等待CPU调度。",
    "source": "文档中「线程的生命周期」-「线程生命周期的状态」部分",
    "hint": "生命周期的第一步是什么？"
  },
  {
    "question": "在多线程通信中，当一个线程调用了某个对象的 `wait()` 方法后，会发生什么？",
    "options": [
      "线程进入等待状态，但仍然持有该对象的锁。",
      "线程继续运行，但会通知其他等待该对象的线程。",
      "线程进入等待状态，并立即释放该对象的锁，以便其他线程可以获取。",
      "线程直接进入终止状态（Terminated）。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "`wait()` 方法的一个关键特性是，它不仅使当前线程进入等待状态，还会释放它所持有的对象监视器锁。这允许其他线程进入该对象的同步代码块或同步方法，并可能调用 `notify()` 或 `notifyAll()` 来唤醒等待的线程。",
    "source": "文档中「线程之间的通讯」-「wait() 方法」部分",
    "hint": "如果调用 `wait()` 的线程不释放锁，其他线程如何进入临界区来唤醒它呢？"
  },
  {
    "question": "文档中描述的线程死锁（Deadlock）需要满足四个条件。以下哪一项不属于这四个必要条件？",
    "options": [
      "请求与保持条件 (Hold and Wait)",
      "互斥条件 (Mutual Exclusion)",
      "线程优先级反转 (Priority Inversion)",
      "循环等待条件 (Circular Wait)"
    ],
    "correctAnswerIndex": 2,
    "explanation": "文档中明确指出了导致线程死锁的四个条件是：互斥条件、请求与保持条件、不剥夺条件和循环等待条件。线程优先级反转是一个与线程调度相关的问题，但它不是死锁发生的四个经典必要条件之一。",
    "source": "文档中「线程死锁」-「线程死锁的原因」部分",
    "hint": "回顾一下死锁成因的四个经典条件，有一个选项描述的是调度问题而非资源竞争的逻辑闭环。"
  },
  {
    "question": "为了解决多个线程访问共享资源时可能产生的数据不一致问题，文档中提到的“同步（Synchronization）”机制主要目的是什么？",
    "options": [
      "让多个线程的执行速度保持一致。",
      "确保多个线程在访问共享资源时按照一定的顺序依次进行，避免并发访问冲突。",
      "在线程执行出错时，自动回滚所有操作。",
      "减少线程创建和销毁的系统开销。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "同步的核心目的是控制对共享资源的并发访问。通过使用如 `synchronized` 关键字等机制，可以保证在同一时刻只有一个线程能够执行特定的代码块或方法，从而避免数据竞争和不一致性问题。",
    "source": "文档中「线程的同步与互斥」-「同步（Synchronization）」部分",
    "hint": "同步是为了解决“抢”资源的问题，它的作用是建立一种“秩序”。"
  },
  {
    "question": "除了使用 `synchronized` 或 `Lock` 等同步机制外，文档还提到了哪种方法来保障线程安全？",
    "options": [
      "在代码中增加 `Thread.sleep()` 调用，减慢访问速度。",
      "为每个线程分配更多的CPU时间片。",
      "使用不可变对象（Immutable Object）。",
      "将所有共享变量声明为 `public static`。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "文档在“线程安全”一节中列举了多种保障线程安全的手段。除了同步机制，还包括使用线程安全的数据结构（如 `ConcurrentHashMap`）、使用不可变对象以及注意原子性操作等。不可变对象因为其状态在创建后无法被修改，所以它们天然是线程安全的，可以被多个线程自由共享而不会产生数据竞争问题。",
    "source": "文档中「线程安全」-「使用不可变对象」部分",
    "hint": "思考一下，如果一个共享的数据从一开始就不能被任何线程修改，还会存在安全问题吗？"
  }
];
        console.log("Quiz Data:", JSON.parse(JSON.stringify(quizData))); // 添加这行用于调试，以可展开的JSON格式输出
        
        let currentQuestionIndex = 0;
        let score = 0;
        // 存储每个问题的回答状态
        const userAnswers = new Array(quizData.length).fill(null); 

        const questionTextEl = document.getElementById('question-text');
        const optionsListEl = document.getElementById('options-list');
        const resultContainerEl = document.getElementById('result-container');
        const quizContentEl = document.getElementById('quiz-content');
        const progressIndicatorEl = document.getElementById('progress-indicator');
        const prevBtn = document.getElementById('prev-btn');
        const nextBtn = document.getElementById('next-btn');
        const hintBtn = document.getElementById('hint-btn');
        const hintContainerEl = document.getElementById('hint-container');

        function loadQuestion() {
          resultContainerEl.innerHTML = '';
          optionsListEl.innerHTML = '';
          hintContainerEl.style.display = 'none'; // 隐藏提示
          
          if (currentQuestionIndex >= quizData.length) {
            showFinalScore();
            return;
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          const currentQuestion = quizData[currentQuestionIndex];
          questionTextEl.textContent = `(${currentQuestionIndex + 1}/${quizData.length}) ${currentQuestion.question}`;
          
          currentQuestion.options.forEach((optionText, index) => {
            const li = document.createElement('li');
            li.className = 'option-item';
            li.textContent = optionText;
            li.dataset.index = index; // Store index in a data attribute
            // 如果这道题已经回答过，恢复状态
            if (userAnswers[currentQuestionIndex] !== null) {
                if (index === userAnswers[currentQuestionIndex]) {
                    li.classList.add('selected');
                }
            }
            optionsListEl.appendChild(li);
          });

          // 如果已经回答过，直接显示结果
          if (userAnswers[currentQuestionIndex] !== null) {
              const isCorrect = userAnswers[currentQuestionIndex] === currentQuestion.correctAnswerIndex;
              showResult(isCorrect, currentQuestion);
          }
          
          updateNavigationButtons();
          updateProgress();
        }

        function selectOption(optionIndex) {
            userAnswers[currentQuestionIndex] = optionIndex;
            const currentQuestion = quizData[currentQuestionIndex];
            const isCorrect = optionIndex === currentQuestion.correctAnswerIndex;

            // 重新计算分数
            score = userAnswers.reduce((acc, answer, index) => {
                return answer === quizData[index].correctAnswerIndex ? acc + 1 : acc;
            }, 0);

            showResult(isCorrect, currentQuestion);
            updateNavigationButtons();
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        function updateProgress() {
            const answeredQuestions = userAnswers.filter(answer => answer !== null).length;
            const progressPercentage = (answeredQuestions / quizData.length) * 100;
            progressIndicatorEl.style.width = `${progressPercentage}%`;
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        function updateNavigationButtons() {
            prevBtn.style.display = 'block';
            nextBtn.style.display = 'block';
            hintBtn.style.display = 'block'; // 显示提示按钮

            prevBtn.disabled = currentQuestionIndex === 0;
            nextBtn.disabled = false; // 最后一题时，下一题按钮不禁用，而是用于显示报告
            nextBtn.textContent = (currentQuestionIndex === quizData.length - 1) ? '查看报告' : '下一题';
            
            // 如果当前问题没有提示，则禁用提示按钮并隐藏提示内容
            if (!quizData[currentQuestionIndex].hint) {
                hintBtn.disabled = true;
                hintContainerEl.style.display = 'none';
                hintContainerEl.textContent = ''; // 清除旧的提示内容
            } else {
                hintBtn.disabled = false;
            }
        }

        function showResult(isCorrect, questionData) {
            resultContainerEl.innerHTML = ''; // 清空之前的结果
            const resultBox = document.createElement('div');
            resultBox.className = `result-box ${isCorrect ? 'correct' : 'incorrect'}`;
            
            let html = `<h3>${isCorrect ? '回答正确！' : '回答错误'}</h3>`;
            if (!isCorrect) {
                html += `<p><strong>正确答案是：</strong> ${questionData.options[questionData.correctAnswerIndex]}</p>`;
            }
            html += `<div class="explanation-text">${questionData.explanation}</div>`;
            html += `<div class="source-text">来源: ${questionData.source}</div>`;
            
            resultBox.innerHTML = html;
            resultContainerEl.appendChild(resultBox);

            // 禁用所有选项的点击事件，并高亮正确/错误答案
            Array.from(optionsListEl.children).forEach((child, index) => {
                child.style.pointerEvents = 'none';
                // 高亮正确答案
                if (index === questionData.correctAnswerIndex) {
                    child.classList.add('correct'); // 需要添加CSS样式
                    child.style.backgroundColor = '#d4edda';
                    child.style.borderColor = '#c3e6cb';
                }
                // 如果选错了，高亮错误选项
                if (!isCorrect && index === userAnswers[currentQuestionIndex]) {
                    child.classList.add('incorrect'); // 需要添加CSS样式
                    child.style.backgroundColor = '#f8d7da';
                    child.style.borderColor = '#f5c6cb';
                }
            });
        }

        function goToNextQuestion() {
            if (currentQuestionIndex < quizData.length - 1) {
                currentQuestionIndex++;
                loadQuestion();
            } else {
                showFinalScore();
            }
        }

        function goToPreviousQuestion() {
            if (currentQuestionIndex > 0) {
                currentQuestionIndex--;
                loadQuestion();
            }
        }
        
        function showHint() {
            const currentQuestion = quizData[currentQuestionIndex];
            if (currentQuestion.hint) {
                hintContainerEl.textContent = currentQuestion.hint;
                hintContainerEl.style.display = 'block';
            } else {
                hintContainerEl.style.display = 'none';
            }
        }

        function showFinalScore() {
            document.querySelector('.quiz-body').style.display = 'none';
            document.getElementById('quiz-footer').style.display = 'none';

            const correctCount = score;
            const totalQuestions = quizData.length;
            const answeredCount = userAnswers.filter(a => a !== null).length;
            const wrongCount = answeredCount - correctCount;
            const skippedCount = totalQuestions - answeredCount;
            const accuracy = totalQuestions > 0 ? Math.round((correctCount / totalQuestions) * 100) : 0;
            const errorRate = totalQuestions > 0 ? Math.round((wrongCount / totalQuestions) * 100) : 0;

            const finalScoreHtml =
                '<div class="final-score-container">' +
                '<h2>答题报告</h2>' +
                '<div class="score-summary">' +
                '<div class="score-card">' +
                '<h3>得分</h3>' +
                '<p>' + correctCount + ' / ' + totalQuestions + '</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>正确率</h3>' +
                '<p>' + accuracy + '%</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>错误率</h3>' +
                '<p>' + errorRate + '%</p>' +
                '</div>' +
                '<div class="score-card score-details">' +
                '<table>' +
                '<tr><td>正确</td><td>' + correctCount + '</td></tr>' +
                '<tr><td>错误</td><td>' + wrongCount + '</td></tr>' +
                '<tr><td>未答</td><td>' + skippedCount + '</td></tr>' +
                '</table>' +
                '</div>' +
                '</div>' +
                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

            let reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  